For example, in a flow counter used to measure the amount of water usage on a water meter, an impeller arranged at some midpoint of a duct rotates when water flows through the duct and the rotation of the impeller is transmitted to a pilot or digit wheel via a plurality of gears. Accordingly, an operator can visually check usage conditions of water based on the rotation of the pilot or the rotation of the digit wheel.
FIGS. 1 and 2 are diagrams schematically showing such conventional flow counter 100. FIG. 1 is a plan view schematically showing conventional flow counter 100. FIG. 2 is a plan view schematically showing an internal structure (mechanism) of flow counter 100 in FIG. 1.
In flow counter 100 shown in these diagrams, the rotation of an impeller in a water pipe (not shown) is transmitted to driving gear 101 in a center section. The rotation of driving gear 101 is transmitted to pilot 103 via pilot gear 102. The rotation of pilot gear 102 is decelerated and transmitted via rotation to digit wheel 111a1 of the least significant digit via a plurality of gears 104 to 110 arranged consecutively. Digit wheels 111a1 to 111a5 are formed substantially in a disk shape. The numbers 0 to 9 are written on a circumferential surface of digit wheels 111a1 to 111a5 at regular intervals. Spindles 112 and 113 of digit wheels 111a1 to 111a5 are rotatably supported on the bottom plate 114 side. Flow counter 100 has five digit wheels 111a1 to 111a5 arranged therein to indicate the amount of water usage by numbers of the first digit to the fifth digit. If the digit wheel (111a1) of the lower-order digit between two adjacent digit wheels (111a1 and 111a2, for example) makes one rotation, the digit wheel (111a2) of the higher-order digit makes a 1/10 rotation (see patent literature 1). Gear 107 of the plurality of gears 104 to 110 consecutively arranged rotates first pointer 115 and gear 109 rotates second pointer 116.